telecom@ucbvax.UUCP (12/16/85)
This is really a half-duplex modem that has a medium amount of buffering to try "simulate" full-duplex. It REQUIRES very rigorous flow control both in and out of both sites. The problem is that its effective throughput may drop suddenly, which can result in the sending site flooding it with data, or it may feed data into the receiving site so quickly that data will be lost (a very common problem). It cannot really be used for most interactive applications, nor can it be used effectively with most existing file transfer software without significant modifications to that software. The issue is that just because the modems transfer the data without error between the modems, doesn't mean that the data is correct from CPU to CPU, given the complexities of flow control involved. I'm still waiting to see some true FULL-DUPLEX modems that avoid these sorts of problems. --Lauren--